- Genetics
- Exon Sequencing of HNF1β in Chinese Patients with Early-Onset Diabetes
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Siqian Gong, Hong Lian, Yating Li, Xiaoling Cai, Wei Liu, Yingying Luo, Meng Li, Si-min Zhang, Rui Zhang, Lingli Zhou, Yu Zhu, Qian Ren, Xiuying Zhang, Jing Chen, Jing Wu, Xianghai Zhou, Xirui Wang, Xueyao Han, Linong Ji
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Received March 20, 2024 Accepted July 24, 2024 Published online November 13, 2024
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DOI: https://doi.org/10.4093/dmj.2024.0159
[Epub ahead of print]
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Abstract
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- Background
Maturity-onset diabetes of the young (MODY) due to variants of hepatocyte nuclear factor 1-beta (HNF1β) (MODY5) has not been well studied in the Chinese population. This study aimed to estimate its prevalence and evaluate the application of a clinical screening method (Faguer score) in Chinese early-onset diabetes (EOD) patients.
Methods Among 679 EOD patients clinically diagnosed with type 2 diabetes mellitus (age at diagnosis ≤40 years), the exons of HNF1β were sequenced. Functional impact of rare variants was evaluated using a dual-luciferase reporter system. Faguer scores ≥8 prompted multiplex ligation-dependent probe amplification (MLPA) for large deletions. Pathogenicity of HNF1β variants was assessed following the American College of Medical Genetics and Genomics (ACMG) guidelines.
Results Two rare HNF1β missense mutations (E105K and G454R) were identified by sequencing in five patients, showing functional impact in vitro. Another patient was found to have a whole-gene deletion by MLPA in 22 patients with the Faguer score above 8. Following ACMG guidelines, six patients carrying pathogenic or likely pathogenic variant were diagnosed with MODY5. The estimated prevalence of MODY5 in Chinese EOD patients was approximately 0.9% or higher.
Conclusion MODY5 is not uncommon in China. The Faguer score is helpful in deciding whether to perform MLPA analysis on patients with negative sequencing results.
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